1. Field
This disclosure relates generally to signal processing, and more specifically, to Fourier transform processing and twiddle factor generation.
2. Related Art
Increasingly signal processing applications require implementation of several different sizes of Fourier transforms, such as Fast Fourier Transforms (FFTs) and Discrete Fourier Transforms (DFTs). By way of example, 3GPP long term evolution (LTE) requires over 40 different sizes of the Fourier transforms. Typically, the Fourier transforms are computed using twiddle factors. In particular, twiddle factors are the coefficients that are used to compute the FFTs and DFTs. Prior to computing the Fourier transforms, the twiddle factors are generated. The Fourier transforms are then computed using the twiddle factors that may be stored in look up tables.
In traditional approaches to computing the Fourier transforms, twiddle factors are duplicated across several look up tables. This is particularly a problem while computing the Fourier transforms based on mixed radices. Duplication of the twiddle factors across several look up tables results in inefficient use of storage in signal processors. Accordingly, there is a need for improved systems and methods for computing the Fourier transforms using twiddle factors.